By Lilla Ross
A group of students got an unforgettable science lesson in May 2013—but just how unforgettable is only now coming to light. While on an expedition in the Azores some 950 miles west of Portugal, as many as four beaked whales surfaced and spent about 10 minutes near a small inflatable boat, giving the instructors time to capture underwater footage of the whales.
But not just any whales: A study in PeerJ reports they turned out to be the rarely seen True’s beaked whales, which were first described in 1912 and had never been filmed underwater.
Only seven live sightings had previously been recorded—and New Scientist points out not all were verified—in part because of the elusive whales’ behavior: a brief surfacing followed by dives that can last up to two hours and take the creatures as deep as two miles down.
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That discovery could be a sort of wrench, explains senior author Emma Carroll, who says “it might be more difficult to tell the different beaked whale species apart in the wild than previously thought” as the Cuvier’s beaked whale bears similar coloration.
But there’s a flip side to the coin: More data on their markings could also make it easier for scientists to identify the whales. New Scientist explains that most such data to date comes from stranded whales, whose coloration can be darkened by the sun.
Getting better at identifying them could allow scientists to do something they’ve never done before: estimate just how many True’s beaked whales are out there. (This is the deepest-diving mammal on the planet.)
This article originally appeared on Newser: Underwater Video From 2013 Ended Up Being a Big Deal